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PostPosted: Wed Nov 19, 2014 10:50 am 
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H5N8 sequences from poultry outbreaks in Germany, the Netherlands, and England match sequences in Korea and China, signaling a migration similar to the 2005/2006 season when the Qinghai stain (clade 2.2) was identified at Qinghai Lake in China in migratory birds (concentrated in bar headed geese) in the Spring, which was followed by outbreaks in northwest China, Kazakhstan, Russia and Mongolia over the summer, and then fall migration moved the strain to Romania, Ukraine, and Turkey followed by spread in Europe as well as migration to the Middle East (Israel and Egypt). In early 2006 the geographic reach expanded to south Asia (India and Afghanistan) as well as western Africa (Nigeria, Ivory Coast, Ghana, and Cameroon).

Although all of the above H5N1 sequences were the Qinghai strain regardless of host (wild birds, poultry, humans. other mammals), several groups maintained that the involvement of wild birds in the vectoring of the Qinghai H5N1 was unclear. This initial lack of clarity was linked to the first two publications on clade 2.2 at Qinghai Lake in back to back papers in Nature and Science by groups in mainland China and Hong Kong. Although both groups agreed that the sequences were virtually identical and represented a novel sub-clade which had PB2 E627K and was present in multiple species of long range migratory birds (dominated by bar headed geese), comments on linkages to prior sequences differed. The China group noted similarities with an earlier outbreak in Korea and Japan, which implicated a wild bird origin, while the group from Hong Kong cited the relationship with a poultry sequence from China (Guinea fowl in Shantou).

The geographic associations may have been impacted by the presence of E627K which has been noted in a sub-set of human cases in the 1997 outbreak in Hong Kong. E627K was found in seasonal flu and lab experiments showed that its presence produced optimal polymerase activity at lower temperatures (33 C), which were closer to the temperature of a human nose in the winter, than body temperature of a bird (41C) which was closer to optimal polymerase activity for PB1 with an E at position 627.

E627K was also linked to a more virulent H5N1 in mice as well as neurotropism as well as a higher concentration in the upper respiratory tract (as compared to levels in the gut or feces). The Hong Kong group's surveillance in China largely used poultry or wild bird droppings, which would have a low or undetectable level of Qinghai H5N1, which would under represent Qinghai H5N1 in southern China.

However, the above two descriptions of the origins of Qinghai H5N1 in wild birds led to a claim of "wild birds as victims" citing infection of wild birds by poultry and a limited role of wild birds in H5N1 vectoring.

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PostPosted: Wed Nov 19, 2014 11:04 am 
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The role of wild birds in the vectoring of H5N1 became increasingly apparent in the summer of 2005. The deaths of the wild birds at Qinghai Lake was unusual because waterfowl had some immunity to H5N1 due in part to low path H5 which produced cross reacting antibodies. Clades 1, 2.1, and 2.3 would kill chickens, but waterfowl was frequently immune and were asymptomatic or had mild symptoms.

At Qinghai Lake, the role of H5N1 in the massive fatalities in the waterfowl was initially denied, but subsequent testing and sequencing clearly implicated the novel H5N1 in the deaths. However, it was possible that the strain would burn itself out at Qinghai Lake and would not present a widespread problem. This possibility was diminished by reports of deaths of waterfowl on farms ion northwest China, indicating the deaths were linked to Qinghai H5N1 and the outbreaks were following the migratory pathway of long range waterfowl which fly to the southern border of Russia shared by Kazakhstan and Mongolia.

Summer outbreaks in these three countries indicated Qinghai did not burn itself in the spring, but was transported to these three countries (which had never reported high path H5N1 previously) by long range migratory birds, and sequencing confirmed the Qinghai strain in all three countries.

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PostPosted: Wed Nov 19, 2014 11:11 am 
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Reports coming out of Russia strongly implicated wild birds. OIE reports noted that initial cases on farms were linked to those with free range birds that shared ponds with migratory birds. Moreover sequence data showed that the H5N1 was the Qinghai strain, which had also been found in an asymptomatic wild bird.

Conservation groups had downplayed the role of wild birds by citing two arguments ("wild birds as victims" claimed that the wild birds were infected with H5N1 by poultry, and "dead birds don't fly" maintained that H5N1 was too lethal to be transported over long distance by wild birds).

However, the presence of Qinghai H5N1 in an asymptomatic wild bird destroyed the "dead birds don't fly argument" and the appearance of the Qinghai starin in countries which had no prior reports of the strain in poultry countered the "wild birds as victims" argument.

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PostPosted: Wed Nov 19, 2014 11:39 am 
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Although the data from Russia and Kazakhstan in the summer of 2005 left little doubt that the spread of Qinghai H5N1 was being driven by wild birds, conservation groups linked to characterizing a wild bird outbreak at Erkhel Lake in Mongolia continued to argue against wild birds.

Initial statements predicted that H5N1 would not be found because the mortality rate was much lower than the massive outbreak at Qinghai Lake. This prediction ignored the possibility that the version of H5N1 that spread to Russia, Kazakhstan, and Mongolia was less lethal in wild birds leading to more effective long range spread.

Even after H5N1 was confirmed, predictions were made that it would not spread because cloacal swabs of live birds were negative. These negatives carried little weight because the Qinghai was present at high concentrations in the upper respiratory tract, and was largely undetectable in cloacal swabs or droppings.

After H5N1 did spread to Europe, the Middle East, and northern Africa, these same groups used the insensitive assay targeting droppings to claim that the H5N1 found in poultry and people in these locations was not due to wild birds because of limited contact and negative wild bird droppings.

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PostPosted: Wed Nov 19, 2014 12:06 pm 
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Although the sequence data and the presence of Qinghai H5N1 in an asymptomatic wild bird left little doubt that wild birds were responsible for the spread, ProMED launched a campaign that created confusion in the media for years. ProMED was closely followed by the media in part because of the SARS outbreak in 2002/2003. ProMED had the most accurate data on the outbreak in China in early 2003 and had extensive subsequent coverage, which increased views by reporters and the general public.

Thus, when ProMED allowed the conservation groups to post their "dead birds don't fly" and wild birds as victims" arguments, an artificial controversy was created. This" controversy" was maintained by ProMED for years when they published reports under the "wild bird or poultry" title.

The two arguments were effectively destroyed in the summer of 2005 due to linkage of the Qinghai strain in wild birds (including asymptomatic) as well as the spread to countries which had no prior reports of such infections in poultry (and all H5N1 in wild birds, poultry, or humans was the Qinghai strain).

The summer data was subsequently bolstered in the fall when H5N1 spread to Europe and appeared in wild birds that followed well established migration pathways and stops at key deltas in Russia (Volga), Romania (Danube), and Egypt (Nile) as well as the Crimean Peninsula.

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PostPosted: Wed Nov 19, 2014 12:14 pm 
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In the fall wild birds migrate out of summer locations in Russia, Kazakhstan, and Mongolia, and the appearance of Qinghai H5N1 in Europe followed that pathway. Moreover, many of the initial fatalities were in swans, which represent waterfowl not easily killed by H5N1 strains that are not Qinghai. Sequences from the dead swans were uniformly Qinghai, the findings in waterfowl followed traditional migration pathways, with cases reported in Russia in the Volga Delta, Romania/Ukraine at the Danube Delta, as well as Ukraine on the Crimean Peninsula. Cases in the Nile Delta were seen in late 2005, but not reported until 2006.

Once again the migration was to locations that were well known stops of migratory birds and all sequences were the Qinghai strain (in locations which had no prior reports of highly pathogenic H5N1 linked to sequences from Asia.

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PostPosted: Wed Nov 19, 2014 12:22 pm 
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Although H5N1 reports from Europe were largely concentrated in eastern Europe, the confirmation of human cases in Turkey in early 2006 dramatically changed reporting. In the fall of 2005 Recombinomics predicted human H5N1 cases based on the acquisition of S227N via recombination between H5N1 and H9N2 sequences. It was known that S227N was linked to mammals in general and upper respiratory tract transmission due to alterations in the receptor binding domain. Donor sequences had been noted in H9N2 sequences in the Middle East, and it was predicted that Qinghai H5N1 in the Middle East would lead to a recombinant with S227N.

In early 2006 reports began to emerge on a cluster of cases in children in a family in eastern Turkey. Sequence data confirmed the presence of S227N and virtually all reported cases in Turkey were from clusters.

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PostPosted: Wed Nov 19, 2014 12:27 pm 
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The H5N1 cases in Turkey was followed by additional human cases in Azerbaijan, Iraq, and Egypt, which had additional receptor binding domain changes (and all sequences also had PB2 E627K). These cases were followed by more widespread reporting of H5N1 in western Europe, the Middle East, Western Africa, and South Asia. All of these reports were in countries which had no prior reports of Asian H5N1 and all sequences from wild birds, poultry, humans, or other mammals, were the Qinghai strain.

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PostPosted: Fri Nov 21, 2014 12:16 pm 
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First European outbreak of avian influenza H5N8 confirmed in poultry

21-11-2014
Germany, the Netherlands and the United Kingdom have recently identified outbreaks of avian influenza. The first was reported on 5 November 2014 on a turkey farm in Mecklenburg-Vorpommern, Germany. The virus was identified as highly pathogenic avian influenza H5N8. This is the first detection of this strain of avian influenza, also called bird flu, in Europe, although outbreaks continue in wild birds and poultry in Asia (China, Japan and the Republic of Korea). How the virus reached Europe is unknown, but testing in Germany revealed that the virus is similar to the one currently circulating in Asia.

The Netherlands outbreak was on a chicken farm in Hekendorp, north-east of Rotterdam; the virus was confirmed as H5N8 on 15 November 2014. A subsequent outbreak on a duck-breeding farm in East Yorkshire, United Kingdom was confirmed as H5N8 on 18 November. Since then two more outbreaks have been detected in the Netherlands. These are also caused by H5 viruses, but exact virological details will not be known until testing has been concluded.

Risk to the general public?
No cases of H5N8 in human beings are known, and the risk to the general public is extremely low. Nevertheless, national authorities are taking appropriate precautions as some avian influenza viruses can infect humans, and other H5 viruses (such as H5N1) have affected humans in the past. The H5N8 virus in Europe appears to be highly pathogenic, meaning that it is highly likely to cause disease and death in poultry. People in close contact with live poultry should watch out for any signs of illness in their flocks and immediately inform their veterinarians if they notice any cause of concern.
It is safe to eat properly cooked poultry products.

What authorities are doing
Veterinary and public health authorities are working together according to national, European Union (EU) and WHO guidelines, and have taken every reasonable precaution. For example, a protection zone and a surveillance zone have been put in place around affected premises to prevent the spread of disease. The poultry affected by the outbreak are being culled by personnel wearing personal protective equipment. They and anyone working on a farm who might have been exposed are being monitored and offered antiviral medication as a precaution. Their contacts are also being monitored for 10 days.

http://www.euro.who.int/en/health-topic ... in-poultry

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